Zengi Captures Edessa, the First Crusader State to Fall

On December 24, 1144, the forces of Imad al-Din Zengi breached the walls of Edessa, ending the Latin rule that the First Crusade had established there. The County of Edessa had been founded in 1098 by Baldwin of Boulogne before the crusaders went on to capture Antioch in northern Syria. Geographically isolated and surrounded by rival Muslim realms such as the Artuqids and Seljuks, Edessa had long been the most vulnerable and sparsely populated of the Crusader states. Its survival relied heavily on delicate alliances and military backing from neighbouring Latin rulers, which disintegrated rapidly in the early 1140s.

The geopolitical situation around Edessa deteriorated significantly following the deaths of Emperor John II Comnenus and King Fulk of Jerusalem in 1143. John's successor, Manuel I Comnenus, was forced to concentrate on securing his domestic standing, while Jerusalem transitioned to the joint rule of Queen Melisende and her young son Baldwin III. At the same time, Count Joscelin II of Edessa had alienated potential local allies by quarrelling with both Raymond II of Tripoli and Raymond of Poitiers, the Prince of Antioch. Left with fewer regional defenders, Joscelin allied with Kara Arslan, the Artuqid ruler of Diyarbakir, to counter Zengi, the atabeg of Mosul and Aleppo.